Wound Dressing Cryogel Materials Based on Poly(vinyl alcohol), Hyaluronic Acid, and Ag₂O Nanoparticles

Hydrogel materials based on poly(vinyl alcohol) (PVA) and silver nanoparticles are used as wound dressings. However, chemical reducing agents, ultraviolet irradiation, and radiation irradiation are mainly used to reduce silver ions to nanoparticles in hydrogel dressings. In this study, polymeric cryogel materials based on poly(vinyl alcohol), hyaluronic acid (HA), and Ag₂O nanoparticles were synthesized by reducing silver ions with hyaluronic acid followed by freezing and thawing of the samples. Structural features, thermophysical, mechanical, antimicrobial, cytotoxic and genotoxic properties of PVA-Ag-HA polymeric cryogel materials were studied by wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical tests, antimicrobial, cytotoxic and genotoxic studies. Studies of cryogel materials using wide-angle X-ray scattering showed that the PVA-HA composite has a higher degree of crystallinity compared to the pure PVA. It was found that during the formation of samples, silver ions are reduced in the polymer systems PVA-HA-Ag⁺ at T = 85 °C, within 1 h with the formation of Ag₂O nanoparticles. The addition of hyaluronic acid to the composition of PVA cryogel increases the water absorption of the samples, and a decrease in the freezing time and concentration of nanoparticles leads to an increase in the water absorption of PVA-HA cryogel materials. The thermal stability of all the studied samples, except HA, practically does not change up to a temperature of 200 °C. For the studied cryogel materials, the tensile strength increases with increasing freezing time and concentration of Ag₂O nanoparticles up to 0.5 wt %. PVA-HA-Ag₂O cryogel nanocomposites exhibited antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli at silver oxide nanoparticle concentrations of ≥0.05 wt %. The obtained nanocomposites with low concentrations of Ag₂O nanoparticles were not toxic. They did not inhibit the viability of MDCK and L-929 cell cultures at silver oxide nanoparticle concentrations of ≥0.1 wt %. When studying the genotoxic properties of cryogel materials, no mutagenic and clastogenic activity was detected. The obtained materials have potential applications for the creation of dressings for the treatment of wounds of various infectious nature.